Identification of a motif that mediates polypyrimidine tract-binding protein-dependent internal ribosome entry

Mitchell, S. A., Spriggs, K. A., Bushell, M. , Evans, J. R., Stoneley, M., Le Quesne, J. P.C., Spriggs, R. V. and Willis, A. E. (2005) Identification of a motif that mediates polypyrimidine tract-binding protein-dependent internal ribosome entry. Genes and Development, 19(13), pp. 1556-1571. (doi: 10.1101/gad.339105) (PMID:15998809) (PMCID:PMC1172062)

Abstract

We have identified a novel motif which consists of the sequence (CCU)n as part of a polypyrimidine-rich tract and permits internal ribosome entry. A number of constructs containing variations of this motif were generated and these were found to function as artificial internal ribosome entry segments (AIRESs) in vivo and in vitro in the presence of polypyrimidine tract-binding protein (PTB). The data show that for these sequences to function as IRESs the RNA must be present as a double-stranded stem and, in agreement with this, rather surprisingly, we show that PTB binds strongly to double-stranded RNA. All the cellular 5′ untranslated regions (UTRs) tested that harbor this sequence were shown to contain internal ribosome entry segments that are dependent upon PTB for function in vivo and in vitro. This therefore raises the possibility that PTB or its interacting protein partners could provide a bridge between the IRES-RNA and the ribosome. Given the number of putative cellular IRESs that could be dependent on PTB for function, these data strongly suggest that PTB-1 is a universal IRES-trans-acting factor.

• Item Type: Articles
• Additional Information: This work was supported by grants from the Wellcome Trust (065502/Z/01/Z to S.A.M., and 063233/B/00/Z to M.B.) and the BBSRC (advanced fellowship held by A.E.W., project grant to M.B., project grant funding for K.A.S., M.S.). J.R.E. held an MRC studentship.
• Status: Published
• Refereed: Yes
• Glasgow Author(s) Enlighten ID: Bushell, Professor Martin
• Authors: Mitchell, S. A., Spriggs, K. A., Bushell, M., Evans, J. R., Stoneley, M., Le Quesne, J. P.C., Spriggs, R. V., and Willis, A. E.
• College/School: College of Medical Veterinary and Life Sciences > School of Cancer Sciences
• Journal Name: Genes and Development
• Publisher: Cold Spring Harbor Laboratory Press
• ISSN: 0890-9369
• ISSN (Online): 1549-5477